A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: BURT on 4 Mar 2010 22:14 On Mar 4, 5:33 pm, "Inertial" <relativ...(a)rest.com> wrote: > "mpalenik" <markpale...(a)gmail.com> wrote in message > > news:3128a141-c953-4c0f-aca6-71773e7ea31b(a)o30g2000yqb.googlegroups.com... > > > > > > > On Mar 4, 12:09 pm, Ste <ste_ro...(a)hotmail.com> wrote: > >> On 4 Mar, 16:48, mpalenik <markpale...(a)gmail.com> wrote: > > >> > On Mar 4, 10:19 am, Ste <ste_ro...(a)hotmail.com> wrote: > > >> > > On 4 Mar, 12:19, "Inertial" <relativ...(a)rest.com> wrote: > > >> > > > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >> > > > > Not really, because if the total acceleration is small, then so > >> > > > > is the > >> > > > > speed. > > >> > > > That is a nonsense argument. Acceleration can be small and speeds > >> > > > very > >> > > > large. > > >> > > When I went to school, you could not have a large change of speed > >> > > with > >> > > only a small amount of total acceleration. > > >> > The problem is your use of the term "total acceleration". If by total > >> > acceleration, you mean integral(a dt), then yes, you are correct. > >> > However, there is already a word for integral(a dt) -- it's called > >> > "the change in velocity". The term "total acceleration" isn't > >> > actually defined. Acceleration is defined, velocity is defined, > >> > deltav is defined. But "total acceleration is not". > > >> Essentially, I'm defining "total acceleration" as something akin to > >> total force, > > > The only meaningful definition I know of total force is net force, > > which is simply the sum of all the forces acting on the object. Time > > doesn't enter into that. > > >> so that even though the force may be small, if it > >> continues for a long time then the total force will be the same as if > >> a large force was applied for a short period of time. > > > What you are describing is called impulse, which is the change in > > momentum (integral(F*deltat)). > > >> In this way, if > >> the application of force is what is causing either part or the whole > >> of the time dilation effect, then it is the final speed that counts, > >> not how quickly the object reached that speed. > > > I understand what you're saying, but we wouldn't call this "total > > acceleration." We would simply call this the change in velocity. > > There's nothing exactly wrong with the way you've defined total > > acceleration, it's just that there is no standard definition for the > > term "total acceleration" so people might infer several different > > things by that term--such as the sum of the accelerations due to > > several different forces acting on an object. > > This is the problem when trying to talk to people like STE who have no idea > of the language of physics and make statements that are pure nonsense out of > ignorance. > > If STE wants to talk physics, he first has to learn enough physics to be > able to talk the talk. Otherwise he is wasting everyone's time.- Hide quoted text - > > - Show quoted text - If you accelerate you must pass through every speed inbetween until you reach your end speed. Mitch Raemsch
From: Bruce Richmond on 4 Mar 2010 23:33 On Mar 4, 10:48 am, PD <thedraperfam...(a)gmail.com> wrote: > On Mar 3, 10:59 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > > > > > > > On Mar 3, 11:21 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Mar 2, 8:12 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > > > > > > It is not a function of finite propagation speeds, this we know, > > > > > because we took into account the finite propagation speeds in our > > > > > procedure for determining simultaneity/nonsimultaneity. Do you not > > > > > remember that? > > > > > I beg to differ. It is not a "mere" or "simple" function of finite > > > > propagation speed, but it *is* a function of it IMO. RoS only took it > > > > into account by allowing us to use different time coordinates in each > > > > frame. If the speed of light was infinite there would be no RoS. > > > > I disagree. All that is needed in relativity of simultaneity is a > > > signal speed that can be VERIFIED to be the same from both events by > > > either observer. > > > Well you are going to have problems with that. There is no way to > > *know* that the speed is the same both ways. > > Yes, there is. That's what isotropy experiments have determined. I'm > surprised you weren't aware of this. > Do you mean like this one? http://mysite.verizon.net/cephalobus_alienus/papers/Gagnon_et_al_1988.pdf The author is kind enough to point out problems in some similar experiments, while failing to notice any in his own. For example, has he made any assumption about contraction of his equipment in the direction of motion? Tom Roberts has written posts in this group showing where some of these experiments are in effect two way measurements. > > > > > That is why Einstein > > wrote, "But it is not possible without further assumption to compare, > > in respect of time, an event at A with an event at B. We have so far > > defined only an ``A time'' and a ``B time.'' We have not defined a > > common ``time'' for A and B, for the latter cannot be defined at all > > unless we establish by definition that the ``time'' required by light > > to travel from A to B equals the ``time'' it requires to travel from B > > to A." > > > > Since the distance from the events to the observer is > > > equal, as verifiable at any time by each observer, we learn from this > > > that each observer KNOWS the propagation delays from each event to the > > > observer are equal. This acknowledges the propagation delays > > > completely, but simply allows for verification that they are the same.. > > > Assuming the speed of light is the same in both directions. > > Which is an experimentally confirmed fact. Done well after Einstein's > comments on the matter, by the way. > Provide a link to an experiment and I'll take a look. > > > > > > > > Then the determination of simultaneity or nonsimultaneity of the > > > original events is completely unambiguous: If the observer receives > > > both signals at the same time, then (because the propagation delays > > > are the same) the original events were simultaneous; if the observer > > > receives both signals at different times, then (because the > > > propagation delays are the same) the original events were > > > nonsimultaneous. > > > > Then the frame-dependence of simultaneity follows directly from the > > > experimental *observation* that for the same pair of events, one > > > observer correctly and unambiguously concludes the events were > > > simultaneous, and the other observer correctly and unambiguously > > > concludes the events were nonsimultaneous. > > > > You've mentioned in the past that you found your disbelief in > > > relativity stems from being unable to find a good, understandable > > > explanation of it. I invite you to read back on this thread where I > > > was trying to explain to Ste (who has a similar complaint) how this > > > comes about. > > > No need. Lorentz showed how all frames could measure the speed of > > light to be c. That in effect confirms the second postulate, which is > > the stumbling block for many. > > Well then, you are just *choosing* what you would like to believe. In > this case, lodging a complaint against relativity that it is not well > explained, when you are not interested in pursuing a better > explanation, having settled on LET instead, is a bit on the > disingenuous side. You are reading more into that than what I wrote. I am not choosing LET over SR. They use the same math and I consider them two interpertations of the same thing. The LET interpertation had the advantage, for me, of showing how c + or - v could end up being measured c in all frames. Given that was possible I no longer had any problem accepting the second postulate. Eventually I became aware that the second postulate wasn't so much an assumption as a stipulation. We will consider the speed of light to be our standard. Recently I have been going back and re-reading some of the books I have bought over the years to see if I can come to grips with some of the modern interpertations of SR. After thinking about it for awhile I have realized that my objections about the changing definition of c were petty/anal. An analogy would be that there used to be 24 hours in a day, 60 minutes in an hour, and 60 seconds in a minute. Now we have defined a second as so many transitions of an atom, and can measure the variation in the length of a day. The new way is better. That it is not in perfect agreement with the old doesn't change much. There was nothing sacred about the old. So yes, an old dog can be taught new tricks :) Bruce
From: Jerry on 5 Mar 2010 00:08 On Mar 4, 10:33 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > On Mar 4, 10:48 am, PD <thedraperfam...(a)gmail.com> wrote: > > > Yes, there is. That's what isotropy experiments have determined. I'm > > surprised you weren't aware of this. > > Do you mean like this one? > > http://mysite.verizon.net/cephalobus_alienus/papers/Gagnon_et_al_1988... > > The author is kind enough to point out problems in some similar > experiments, while failing to notice any in his own. > > For example, has he made any assumption about contraction of his > equipment in the direction of motion? Tom Roberts has written posts > in this group showing where some of these experiments are in effect > two way measurements. Do you understand the principle of Gagnon's experiment? Do you understand the inverse relationship between group velocity and phase velocity that exists in a wave guide? Do you understand that length contraction would be a second order phenomenon, while Gagnon's experiment should be sensitive to first order, assuming an anisotropy exists? Do you understand that Gagnon's experiment is a true one-clock measurement of OWLS anisotropy? Do you understand the difference between an attempt to detect OWLS anisotropy versus an attempt to perform a one way light speed measurement? On the negative side, I probably know a lot more about defects in Gagnon's experiment than you have ever dreamed of. Gagnon drove the wave guides near cutoff. What does that imply about heating? Take a good look at the test theory that they used to analyze their results. Do you notice something about its internal consistency in terms of an important criterion that I shall not name, but which you ought to be aware of? Is the fact that the test theory does not meet this standard of internal consistency important in their analysis? Can you guess what this problem is? Can you guess why I consider Gagnon et al. to be an important experiment, despite some problems in analysis? Start with the basics. I've given you important clues. How does Gagnon et al's xperiment work? > Recently I have been going back and re-reading some of the books I > have bought over the years to see if I can come to grips with some of > the modern interpertations of SR. After thinking about it for awhile > I have realized that my objections about the changing definition of c > were petty/anal. An analogy would be that there used to be 24 hours > in a day, 60 minutes in an hour, and 60 seconds in a minute. Now we > have defined a second as so many transitions of an atom, and can > measure the variation in the length of a day. The new way is better. > That it is not in perfect agreement with the old doesn't change much. > There was nothing sacred about the old. So yes, an old dog can be > taught new tricks :) Thank goodness! Jerry
From: Inertial on 5 Mar 2010 00:12 "Bruce Richmond" <bsr3997(a)my-deja.com> wrote in message news:7806715d-93d2-49ff-ad67-6dac8ea64d8c(a)e7g2000yqf.googlegroups.com... > On Mar 4, 10:48 am, PD <thedraperfam...(a)gmail.com> wrote: >> On Mar 3, 10:59 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: >> >> >> >> >> >> > On Mar 3, 11:21 am, PD <thedraperfam...(a)gmail.com> wrote: >> >> > > On Mar 2, 8:12 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: >> >> > > > > It is not a function of finite propagation speeds, this we know, >> > > > > because we took into account the finite propagation speeds in our >> > > > > procedure for determining simultaneity/nonsimultaneity. Do you >> > > > > not >> > > > > remember that? >> >> > > > I beg to differ. It is not a "mere" or "simple" function of finite >> > > > propagation speed, but it *is* a function of it IMO. RoS only took >> > > > it >> > > > into account by allowing us to use different time coordinates in >> > > > each >> > > > frame. If the speed of light was infinite there would be no RoS. >> >> > > I disagree. All that is needed in relativity of simultaneity is a >> > > signal speed that can be VERIFIED to be the same from both events by >> > > either observer. >> >> > Well you are going to have problems with that. There is no way to >> > *know* that the speed is the same both ways. >> >> Yes, there is. That's what isotropy experiments have determined. I'm >> surprised you weren't aware of this. >> > > Do you mean like this one? > > http://mysite.verizon.net/cephalobus_alienus/papers/Gagnon_et_al_1988.pdf > > The author is kind enough to point out problems in some similar > experiments, while failing to notice any in his own. > > For example, has he made any assumption about contraction of his > equipment in the direction of motion? Tom Roberts has written posts > in this group showing where some of these experiments are in effect > two way measurements. > >> >> >> >> > That is why Einstein >> > wrote, "But it is not possible without further assumption to compare, >> > in respect of time, an event at A with an event at B. We have so far >> > defined only an ``A time'' and a ``B time.'' We have not defined a >> > common ``time'' for A and B, for the latter cannot be defined at all >> > unless we establish by definition that the ``time'' required by light >> > to travel from A to B equals the ``time'' it requires to travel from B >> > to A." >> >> > > Since the distance from the events to the observer is >> > > equal, as verifiable at any time by each observer, we learn from this >> > > that each observer KNOWS the propagation delays from each event to >> > > the >> > > observer are equal. This acknowledges the propagation delays >> > > completely, but simply allows for verification that they are the >> > > same. >> >> > Assuming the speed of light is the same in both directions. >> >> Which is an experimentally confirmed fact. Done well after Einstein's >> comments on the matter, by the way. >> > > Provide a link to an experiment and I'll take a look. > >> >> >> >> >> >> > > Then the determination of simultaneity or nonsimultaneity of the >> > > original events is completely unambiguous: If the observer receives >> > > both signals at the same time, then (because the propagation delays >> > > are the same) the original events were simultaneous; if the observer >> > > receives both signals at different times, then (because the >> > > propagation delays are the same) the original events were >> > > nonsimultaneous. >> >> > > Then the frame-dependence of simultaneity follows directly from the >> > > experimental *observation* that for the same pair of events, one >> > > observer correctly and unambiguously concludes the events were >> > > simultaneous, and the other observer correctly and unambiguously >> > > concludes the events were nonsimultaneous. >> >> > > You've mentioned in the past that you found your disbelief in >> > > relativity stems from being unable to find a good, understandable >> > > explanation of it. I invite you to read back on this thread where I >> > > was trying to explain to Ste (who has a similar complaint) how this >> > > comes about. >> >> > No need. Lorentz showed how all frames could measure the speed of >> > light to be c. That in effect confirms the second postulate, which is >> > the stumbling block for many. >> >> Well then, you are just *choosing* what you would like to believe. In >> this case, lodging a complaint against relativity that it is not well >> explained, when you are not interested in pursuing a better >> explanation, having settled on LET instead, is a bit on the >> disingenuous side. > > You are reading more into that than what I wrote. I am not choosing > LET over SR. They use the same math Yes > and I consider them two > interpertations of the same thing. Not at all. Very different as far as how they explain reality LET has and required a fixed (theoretically undetectable) aether in a fixed absolute frame. SR does not specify nor require anything about an aether LET has objects physically compressed due to absolute motion thru the aether SR has no absolute motion, so objects are not affected by such motion LET has processes physically slowed due to absolute motion thru the aether SR has no absolute motion, so processes are not affected by such motion LET has a side-effect of the speed of light being measured as the same in all frames of reference, due to measuring with compressed rulers and slowed clocks, even though its only really has that speed relative to the aether, SR has no absolute compression and slowing, and the speed of light really is c LET has a side-effect of an appearance of the lorentz transforms holding on measured values, due to measuring with compressed rulers and slowed clocks. SR has no absolute compression and slowing, so the lorentz transform hold > The LET interpertation had the > advantage, for me, of showing how c + or - v could end up being > measured c in all frames. In SR there is no c+v or c-v, because there is no fixed absolute aether frame in which light really travels at c. > Given that was possible I no longer had any > problem accepting the second postulate. Eventually I became aware > that the second postulate wasn't so much an assumption as a > stipulation. We will consider the speed of light to be our standard. No .. it is an observed fact. Not a stipulation > Recently I have been going back and re-reading some of the books I > have bought over the years to see if I can come to grips with some of > the modern interpertations of SR. After thinking about it for awhile > I have realized that my objections about the changing definition of c > were petty/anal. :) Always a good conclusion to reach .. it shows you really are thinking and learning and advancing. > An analogy would be that there used to be 24 hours > in a day, 60 minutes in an hour, and 60 seconds in a minute. Now we > have defined a second as so many transitions of an atom, and can > measure the variation in the length of a day. The new way is better. > That it is not in perfect agreement with the old doesn't change much. > There was nothing sacred about the old. So yes, an old dog can be > taught new tricks :) > > Bruce And several points up my estimation ladder for doing so and admitting it :):)
From: BURT on 5 Mar 2010 00:23
On Mar 4, 9:12 pm, "Inertial" <relativ...(a)rest.com> wrote: > "Bruce Richmond" <bsr3...(a)my-deja.com> wrote in message > > news:7806715d-93d2-49ff-ad67-6dac8ea64d8c(a)e7g2000yqf.googlegroups.com... > > > > > > > On Mar 4, 10:48 am, PD <thedraperfam...(a)gmail.com> wrote: > >> On Mar 3, 10:59 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > > >> > On Mar 3, 11:21 am, PD <thedraperfam...(a)gmail.com> wrote: > > >> > > On Mar 2, 8:12 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > > >> > > > > It is not a function of finite propagation speeds, this we know, > >> > > > > because we took into account the finite propagation speeds in our > >> > > > > procedure for determining simultaneity/nonsimultaneity. Do you > >> > > > > not > >> > > > > remember that? > > >> > > > I beg to differ. It is not a "mere" or "simple" function of finite > >> > > > propagation speed, but it *is* a function of it IMO. RoS only took > >> > > > it > >> > > > into account by allowing us to use different time coordinates in > >> > > > each > >> > > > frame. If the speed of light was infinite there would be no RoS. > > >> > > I disagree. All that is needed in relativity of simultaneity is a > >> > > signal speed that can be VERIFIED to be the same from both events by > >> > > either observer. > > >> > Well you are going to have problems with that. There is no way to > >> > *know* that the speed is the same both ways. > > >> Yes, there is. That's what isotropy experiments have determined. I'm > >> surprised you weren't aware of this. > > > Do you mean like this one? > > >http://mysite.verizon.net/cephalobus_alienus/papers/Gagnon_et_al_1988... > > > The author is kind enough to point out problems in some similar > > experiments, while failing to notice any in his own. > > > For example, has he made any assumption about contraction of his > > equipment in the direction of motion? Tom Roberts has written posts > > in this group showing where some of these experiments are in effect > > two way measurements. > > >> > That is why Einstein > >> > wrote, "But it is not possible without further assumption to compare, > >> > in respect of time, an event at A with an event at B. We have so far > >> > defined only an ``A time'' and a ``B time.'' We have not defined a > >> > common ``time'' for A and B, for the latter cannot be defined at all > >> > unless we establish by definition that the ``time'' required by light > >> > to travel from A to B equals the ``time'' it requires to travel from B > >> > to A." > > >> > > Since the distance from the events to the observer is > >> > > equal, as verifiable at any time by each observer, we learn from this > >> > > that each observer KNOWS the propagation delays from each event to > >> > > the > >> > > observer are equal. This acknowledges the propagation delays > >> > > completely, but simply allows for verification that they are the > >> > > same. > > >> > Assuming the speed of light is the same in both directions. > > >> Which is an experimentally confirmed fact. Done well after Einstein's > >> comments on the matter, by the way. > > > Provide a link to an experiment and I'll take a look. > > >> > > Then the determination of simultaneity or nonsimultaneity of the > >> > > original events is completely unambiguous: If the observer receives > >> > > both signals at the same time, then (because the propagation delays > >> > > are the same) the original events were simultaneous; if the observer > >> > > receives both signals at different times, then (because the > >> > > propagation delays are the same) the original events were > >> > > nonsimultaneous. > > >> > > Then the frame-dependence of simultaneity follows directly from the > >> > > experimental *observation* that for the same pair of events, one > >> > > observer correctly and unambiguously concludes the events were > >> > > simultaneous, and the other observer correctly and unambiguously > >> > > concludes the events were nonsimultaneous. > > >> > > You've mentioned in the past that you found your disbelief in > >> > > relativity stems from being unable to find a good, understandable > >> > > explanation of it. I invite you to read back on this thread where I > >> > > was trying to explain to Ste (who has a similar complaint) how this > >> > > comes about. > > >> > No need. Lorentz showed how all frames could measure the speed of > >> > light to be c. That in effect confirms the second postulate, which is > >> > the stumbling block for many. > > >> Well then, you are just *choosing* what you would like to believe. In > >> this case, lodging a complaint against relativity that it is not well > >> explained, when you are not interested in pursuing a better > >> explanation, having settled on LET instead, is a bit on the > >> disingenuous side. > > > You are reading more into that than what I wrote. I am not choosing > > LET over SR. They use the same math > > Yes > > > and I consider them two > > interpertations of the same thing. > > Not at all. Very different as far as how they explain reality > > LET has and required a fixed (theoretically undetectable) aether in a fixed > absolute frame. > SR does not specify nor require anything about an aether > > LET has objects physically compressed due to absolute motion thru the aether > SR has no absolute motion, so objects are not affected by such motion > > LET has processes physically slowed due to absolute motion thru the aether > SR has no absolute motion, so processes are not affected by such motion > > LET has a side-effect of the speed of light being measured as the same in > all frames of reference, due to measuring with compressed rulers and slowed > clocks, even though its only really has that speed relative to the aether, > SR has no absolute compression and slowing, and the speed of light really is > c > > LET has a side-effect of an appearance of the lorentz transforms holding on > measured values, due to measuring with compressed rulers and slowed clocks. > SR has no absolute compression and slowing, so the lorentz transform hold > > > The LET interpertation had the > > advantage, for me, of showing how c + or - v could end up being > > measured c in all frames. > > In SR there is no c+v or c-v, because there is no fixed absolute aether > frame in which light really travels at c. > > > Given that was possible I no longer had any > > problem accepting the second postulate. Eventually I became aware > > that the second postulate wasn't so much an assumption as a > > stipulation. We will consider the speed of light to be our standard. > > No .. it is an observed fact. Not a stipulation > > > Recently I have been going back and re-reading some of the books I > > have bought over the years to see if I can come to grips with some of > > the modern interpertations of SR. After thinking about it for awhile > > I have realized that my objections about the changing definition of c > > were petty/anal. > > :) Always a good conclusion to reach .. it shows you really are thinking > and learning and advancing. > > > An analogy would be that there used to be 24 hours > > in a day, 60 minutes in an hour, and 60 seconds in a minute. Now we > > have defined a second as so many transitions of an atom, and can > > measure the variation in the length of a day. The new way is better. > > That it is not in perfect agreement with the old doesn't change much. > > There was nothing sacred about the old. So yes, an old dog can be > > taught new tricks :) > > > Bruce > > And several points up my estimation ladder for doing so and admitting it > :):)- Hide quoted text - > > - Show quoted text - Space contraction leads to flat atoms which do not pass for physics. Mitch Raemsch |